A vulnerability in the request authentication validation for the REST API of Cisco SD-WAN vManage software could allow an unauthenticated, remote attacker to gain read permissions or limited write permissions to the configuration of an affected Cisco SD-WAN vManage instance. This vulnerability is due to insufficient request validation when using the REST API feature. An attacker could exploit this vulnerability by sending a crafted API request to an affected vManage instance. A successful exploit could allow the attacker to retrieve information from and send information to the configuration of the affected Cisco vManage instance. This vulnerability only affects the REST API and does not affect the web-based management interface or the CLI.